JP2016081864A - Power storage module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify the assembly of a power storage module having a gas exhaust structure and obtain an appropriate sealing performance.SOLUTION: A power storage module according to the invention comprises: a plurality of power storage elements; a holder having a plurality of openings into which power storage elements are respectively inserted, and holding one end of each of the power storage elements extending in a predetermined direction; a cover member for defining an exhaust space for gas generated in each power storage element between the holder and it; and a seal member for sealing the exhaust space. The cover member is provided on the second surface side of the holder opposite the first surface side thereof, which faces the exhaust space in a direction in which the cover member is pressed by the pressure of gas. The cover member has a folding part that restricts its movement in a direction in which the cover member is pressed. The seal member is provided between the folding part and the second surface so as to surround the periphery of the plurality of power storage elements. When gas is expelled into the exhaust space, the seal member is compressed in the same direction as the direction in which it is pressed by the folding part.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a power storage module having a structure for discharging gas from a power storage element.

  Patent Document 1 discloses a battery module having a plurality of cylindrical battery cells and having a structure for discharging gas discharged from each battery cell. The end cover provided on the gas discharge valve side of the battery cell is formed in a concave shape, and is fixed to a bus bar plate to which each battery cell is fixed via a seal member.

JP 2009-164085 A

  Since the gas discharged from the battery cell due to the battery abnormality is high temperature and high pressure, a seal member is provided for preventing gas leakage from the discharge space as in Patent Document 1. At this time, in order to obtain the required sealing performance for the high-temperature and high-pressure gas discharged into the discharge space, a high assembly load (compression force) is applied so as to compress the seal member, and the end cover is Must be fixed to the bus bar.

  However, the work of assembling the end cover while applying a load is inferior in workability, and may increase the cost of the assembling work. Further, since the assembly load is always applied to the seal member, the seal member is partially plastically deformed over time, and the required sealing performance cannot be obtained when the gas is discharged from the battery cell. There is a fear.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an appropriate sealing performance for a discharge space when discharging gas from a power storage element while simplifying the assembly work of the power storage module in a power storage module having a gas discharge structure. An object of the present invention is to provide a storage module that can be used.

  The power storage module according to the present invention has a plurality of power storage elements extending in a predetermined direction and arranged side by side in a plane orthogonal to the predetermined direction, and a plurality of openings into which the plurality of power storage elements are respectively inserted. A holder for holding one end of each power storage element in a predetermined direction, and a gas generated in the power storage element discharged from a discharge valve provided on one end side of the power storage element exposed from the plurality of openings between the holders A cover member for forming the discharge space; and a seal member for sealing the discharge space. The cover member is provided on the second surface side facing the first surface of the holder facing the discharge space in the direction in which the cover member is pressed by the pressure of the gas discharged into the discharge space, and in the direction in which the cover member is pressed. And a seal member is provided between the folded portion and the second surface so as to surround the periphery of the plurality of power storage elements, and when the gas is discharged into the discharge space, the folded portion Compressed in the same direction as the direction pressed by.

  According to the present invention, the cover member is attached to the holder so that the seal member is compressed in the same direction as the direction pressed by the folded portion while the movement in the direction pressed by the gas pressure is restricted. . Therefore, in a state where the gas is not discharged from the power storage element (a state where the gas is not pressed by the gas pressure), a compressive force for obtaining a sealing performance necessary for preventing gas leakage from the discharge space is not applied to the seal member. However, when the gas is discharged from the power storage element (a state where the gas is pressed by the pressure of the gas), the folded portion applies a compressive force to the seal member to ensure the sealing performance necessary for preventing gas leakage. .

  Therefore, it is possible to simplify the assembling operation of the power storage module having the gas discharge structure, and it is possible to exert an appropriate sealing performance for the discharge space when the gas is discharged from the power storage element.

3 is a top view of the battery module of Example 1. FIG. It is Y1-Y1 sectional drawing of FIG. It is X1-X1 sectional drawing of FIG.

  Examples of the present invention will be described below.

Example 1
A battery module (corresponding to the power storage module of the present invention) that is Example 1 will be described. FIG. 1 is a top view of the battery module. 2 is a cross-sectional view taken along line Y1-Y1 shown in FIG. 3 is a cross-sectional view taken along the line X1-X1 shown in FIG. 1 to 3, the X axis, the Y axis, and the Z axis are axes orthogonal to each other. In this embodiment, the axis extending in the vertical direction is the Z axis. The battery module 1 of the present embodiment can be mounted on, for example, a vehicle such as a hybrid vehicle or an electric vehicle, and is used as a power supply device that supplies power to a traveling motor.

  The battery module 1 includes a plurality of single cells (corresponding to a power storage element of the present invention) 10, a holder 20, a module case 30, and a cover member 40. The number of the single cells 10 constituting the battery module 1 can be set as appropriate. As the unit cell 10, a secondary battery such as a nickel metal hydride battery or a lithium ion battery can be used. An electric double layer capacitor can be used instead of the secondary battery.

  The unit cell 10 is a so-called cylindrical battery. A cylindrical battery is a battery having a cylindrical battery case and a power generation element accommodated in the battery case. The inside of the battery case is sealed. The power generation element is an element that performs charging and discharging. The power generation element includes a positive electrode plate, a negative electrode plate, and a separator disposed between the positive electrode plate and the negative electrode plate. Since the configuration of the power generation element is known, detailed description thereof is omitted.

  The plurality of single cells 10 are arranged in the XY plane. Each unit cell 10 extends in the Z direction. The cross section of the unit cell 10 in the XY plane is formed in a circular shape. For example, a plurality of unit cells 10 are arranged with the X direction as the first arrangement direction, and a plurality of unit cells 10 arranged in the first arrangement direction are arranged with the Y direction as the second arrangement direction. Modules can be formed. The individual cells 10 arranged in the Y direction are displaced in the X direction.

  The holder 20 holds a part of each unit cell 10. The holder 20 has an opening 21 along the outer shape of the unit cell 10, and the unit cell 10 is inserted into the opening 21. As shown in FIG. 2, the lower end surface 12 of each unit cell 10 is disposed along the lower end surface 22 of the holder 20. The number of openings 21 is equal to the number of unit cells 10 constituting the battery module 1. The holder 20 can be made of a metal material such as aluminum metal.

  The unit cell 10 and the opening 21 are insulated. Specifically, by forming a layer formed of an insulating material on the outer surface of the unit cell 10, insulation between the unit cell 10 and the holder 20 can be ensured. Further, by providing a filler of an insulating material between the unit cell 10 and the opening 21, insulation between the unit cell 10 and the holder 20 can be ensured.

  In addition, in the present Example, although the opening part 21 is formed for every single cell 10, it is not restricted to this. That is, it is only necessary that the holder 20 can be used to hold all the unit cells 10 constituting the battery module 1. For example, these single cells 10 can be held by inserting a plurality of single cells 10 into one opening 21.

  Both end surfaces (upper end surface 11 and lower end surface 12) in the longitudinal direction (Z direction) of the unit cell 10 are used as a positive electrode terminal and a negative electrode terminal. That is, one end surface in the longitudinal direction can be used as a positive electrode terminal, and the other end surface can be used as a negative electrode terminal. Here, the positive electrode terminal and the negative electrode terminal are portions (a part of the unit cell 10) connected to a bus bar described later. In the structure shown in FIG. 2, the directions of the positive electrode terminal and the negative electrode terminal can be set as appropriate.

  As shown in FIG. 2, the unit cell 10 has the upper end surface 23 side of the holder 20 covered with a module case 30. The module case 30 can be fixed to the holder 20 so that the lower end of the module case 30 is in contact with the upper end surface 23 of the holder 20.

  A space surrounded by the holder 20 and the module case 30 becomes a moving path of a heat exchange medium used for temperature adjustment of the unit cell 10. For example, a plurality of slits (not shown) that pass through the inside of the module case 30 can be provided on both side surfaces along the X direction of the module case 30. By flowing a heat exchange medium such as air in the Y direction with respect to the module case 30, the heat exchange medium flows into the inside from one side surface of the module case 30 and is discharged out of the module case 30 from the other side surface. A gas (such as air) or a liquid can be used as the heat exchange medium.

  The cover member 40 is provided on the bottom side of the battery module 1 so as to cover the entire lower end surface 22 of the holder 20. Between the cover member 40 and the holder 20, a discharge space S for gas generated in the unit cell 10 discharged from the valve 13 provided on the lower end surface 12 of the unit cell 10 exposed from the plurality of openings 21. Form. The discharge space S surrounded by the holder 20 and the cover member 40 serves as a movement path for the gas discharged from the unit cell 10.

  The cover member 40 is provided with a discharge port 44 that allows the discharge space S to communicate with the outside of the battery module 1. Gas is discharged from the discharge space S to the outside of the battery module 1 through the discharge port 44. A discharge hose that communicates with the outside of the vehicle can be attached to the discharge port 44.

  As shown in FIGS. 2 and 3, the cover member 40 is disposed on one end side in the Z direction (the lower end surface 22 of the holder 20) where the plurality of single cells 10 are held by the holder 20. Mounted from below. The cover member 40 is concave in the Z direction so as to form the discharge space S. The cover member 40 can be made of, for example, a metal material with high heat dissipation.

  The cover member 40 is provided on the lower end surface 22 of the holder 20 on the periphery of the lid portion 41 facing the lower end surfaces 12 of the plurality of single cells 10 exposed from the openings 21 and the lid portion 41 extending in the XY plane. And includes a side wall portion 42 protruding in the Z direction and a folded portion 43 extending inward from the side wall portion 42 in the XY plane. In addition, although the discharge port 44 mentioned above has shown in the example the aspect provided in the cover part 41, it is also possible to provide in the side wall part 42 grade | etc.,.

  The holder 20 is provided with a locking portion 24 that locks the folded portion 43 of the cover member 40 on the periphery extending in the XY plane. The locking portion 24 is a stepped portion having a locking surface 24 a located on the lower end surface 22 side of the upper end surface 23 at the periphery of the holder 20.

  A folded portion 43 of the cover member 40 is disposed above the locking surface 24a. The side wall portion 42 extends upward from the periphery of the cover member 40 to the locking surface 24a through the outside of the end portion in the X direction of the holder 20. The folded portion 43 can be formed by folding the side wall portion 42 extending in the Z direction from the outside to the inside of the X direction end portion of the holder 20 along the locking surface 24 a facing the lower end surface 22. it can.

  The folded portion 43 is disposed substantially parallel to the locking surface 24a on the upper end surface 23 side of the holder 20, and is located above the locking surface 24a. Therefore, as shown in FIG. 2, the cover member 40 is attached so as to hang from the locking portion 24, and movement of the folded portion 43 in a direction approaching the locking surface 24 a is restricted.

  A seal member 60 is provided between the inner surface of the folded portion 43 and the locking surface 24a. In the present embodiment, the discharge space S on the lower end surface 22 side of the holder 20 formed by the cover member 40 is formed on the upper end surface 23 side of the holder 20 facing in the Z direction. Thus, the cover member 40 is attached to the holder 20.

  Here, as shown in FIG. 3, a bus bar 51 is fixed to the lower end surface 12 of the unit cell 10 exposed from the opening 21. A bus bar 52 is fixed to the upper end surface 11 of the unit cell 10. As a method of fixing the bus bars 51 and 52 to the end surfaces 11 and 12, for example, welding can be used.

  The bus bars 51 and 52 are, for example, plate-like members extending in the XY plane, and include a plurality of connection tabs corresponding to the arrangement positions of the plurality of single cells 10. It is included in the battery module 1 by connecting each connection tab of the bus bar 51 and the lower end surface 12 (negative electrode terminal) of the unit cell 10 and connecting each connection tab of the bus bar 52 and the upper end surface 11 (positive electrode terminal). A plurality of single cells 10 can be connected in series or in parallel.

  A valve 13 is provided on the lower end surface 12 of the unit cell 10. The valve 13 discharges the gas generated inside the cell 10 (battery case) to the outside (discharge space S) of the cell 10. Due to overcharging of the unit cell 10 (power generation element) or the like, gas may accumulate inside the unit cell 10 (battery case). Since the battery case is in a sealed state, the pressure (internal pressure) inside the unit cell 10 (the outer can case that houses the power generation element) increases with the generation of gas.

  When the internal pressure of the unit cell 10 rises and reaches the operating pressure of the valve 13, the valve 13 changes from the closed state to the open state. Thereby, the gas existing inside the unit cell 10 passes through the valve 13 and is discharged to the outside of the unit cell 10. As the structure of the valve 13, a known structure can be adopted as appropriate. For example, the valve 13 can be changed from a closed state to an open state by breaking or deforming the valve 13 in accordance with an increase in the internal pressure of the unit cell 10.

  Next, the seal structure of the gas discharge space S of the present embodiment will be described in detail. As shown in FIG. 3, the gas discharged from the valve 13 is blown into the discharge space S from the lower end surface 12 of the unit cell 10. At this time, the gas blown into the discharge space S pushes the lid portion 41 of the cover member 40 facing the valve 13 downward in the Z direction with the pressure. For this reason, the cover part 41 is pressed in the direction away from the lower end surface 22 of the holder 20 by the pressure of gas, as shown with a dotted line.

  Conventionally, the seal portion of the discharge space S is provided on the lower end surface 22 side of the holder 20. For example, a sealing member is provided between the lower end surface 22 and the lid portion 41. Therefore, the load that must be applied to the seal portion in order to exhibit the necessary sealing performance and the direction in which the lid portion 41 is pressed by the gas are reversed in the Z direction. For this reason, it is necessary to attach the cover member 40 to the holder 20 by applying a reverse assembly load to the seal portion with respect to the direction in which the lid portion 41 is pressed by the gas.

  The operation of assembling the cover member 40 to the holder 20 while applying a load is not easy and the workability is poor. Moreover, in order to ensure a necessary sealing function, since the assembly load must always be applied to the seal portion, the seal portion is partially plastically deformed over time, and the cell 10 When the gas was discharged, there was a possibility that the required sealing performance could not be obtained.

  Therefore, the cover member 40 of this embodiment corresponds to the lower end surface 22 (first surface) of the holder 20 facing the discharge space S in the direction in which the cover member 40 is pressed by the pressure of the gas discharged into the discharge space S. Provided on the side of the locking surface 24a (corresponding to the second surface) on the upper end surface 23 side opposite to the upper end surface 23, and is provided with a folded portion 43 that restricts movement in the pressed direction.

  The folded portion 43 and the locking surface 24a are provided on the periphery of the upper end surface 23 of the holder 20 (see FIG. 1), and the folded portion 43 and the locking surface so that the seal member 60 surrounds the plurality of unit cells 10. 24a. When the gas is discharged into the discharge space S, the seal member 60 is compressed in the same direction as the direction in which the cover member 40 (lid portion 41) is pressed so that the folded portion 43 shortens the distance from the locking surface 24a. To do.

  As described above, in this embodiment, the movement of the cover member 40 in the direction pressed by the gas pressure is restricted, and the same direction as the direction pressed by the folded portion 43 when the gas is discharged from the unit cell 10. The seal member 60 is attached to the holder 20 so as to be compressed. For this reason, in a state where the gas is not discharged from the unit cell 10 (a state where the gas is not pressed by the gas pressure), a compression force for obtaining a sealing performance necessary for preventing gas leakage from the discharge space S is applied to the seal member 60. Even if not, when the gas is discharged from the unit cell 10 (a state where the gas is pressed by the gas pressure), the folded portion 43 applies a compressive force to the seal member 60 and is necessary for preventing gas leakage. It can be made to exhibit a sufficient sealing performance.

  As shown in FIG. 3, the seal member 60 can be provided between the inside of the folded portion 43 of the cover member 40 and the locking surface 24 a on the upper end surface 23 side. As indicated by the dotted line, when the lid portion 41 is pressed in a direction away from the lower end surface 22 of the holder 20 due to the gas pressure, the folded portion 43 approaches the locking surface 24a. At this time, the sealing member 60 is loaded by the folded portion 43 in the same direction (arrow P) as the direction in which the lid portion 41 is pressed by the gas pressure (open arrow), and is discharged into the discharge space S. The sealing performance is exhibited by the pressure of the gas, and the gas discharged from the single cell 10 into the discharge space S can be prevented from leaking out of the discharge space S.

  Since the gas is blown into the discharge space S at a high temperature and a high pressure, the folded portion 43 presses the seal member 60 until the gas is discharged from the discharge port 44 of the lid portion 41, and the seal member 60 Necessary sealing function is demonstrated. After the gas is discharged from the discharge port 44 to the outside of the battery module 1, the force that the folded portion 43 approaches the locking surface 24 a, in other words, the force that tries to widen the discharge space S is not applied. The sealing function for is released. In a state where the lid portion 41 is not pressed by the gas pressure, the compression force is not applied to the seal member 60 in order to ensure the sealing performance.

  According to the battery module 1 of the present embodiment, when the cover member 40 is pressed by the pressure of the gas discharged into the discharge space S, the folded portion that restricts the movement of the cover member 40 in the direction away from the holder 20. 43, and a seal member 60 is provided between the folded portion 43 and the locking portion 24a. For this reason, in order to ensure the required sealing performance, it is not necessary to apply a load to the sealing member 60 in advance and assemble the cover member 40 to the holder 20, and the workability of the assembling work can be improved. Since the load (compression force) for obtaining the required sealing performance is applied to the seal member 60 only when gas is generated from the unit cell 10, the seal member 60 is prevented from being sag (plastic deformation, etc.). And the deterioration of the sealing performance can be suppressed.

  The seal member 60 may be disposed between the folded portion 43 and the locking surface 24a. For example, as shown in FIGS. 2 and 3, the seal member 60 is disposed between the folded portion 43 and the locking surface 24a. It can be formed so as to extend from the convex portion to the lower end surface 22 along the locking portion 24. By comprising in this way, the insulation of the metal cover member 40 and the metal holder 20 is securable.

  Moreover, although the step-shaped latching | locking part 24 is formed in the periphery of the upper end surface 23 of the holder 20, it does not restrict to this. For example, the periphery of the upper end surface 23 of the holder 20 can be used as the locking surface 24a. The seal member 60 can be disposed between the periphery of the upper end surface 23 and the folded portion 43.

  Further, in the present embodiment, the embodiment in which the holder 20 is provided on the lower side of the battery module 1 and the discharge space S is provided below the battery module 1 in the battery module 1 is illustrated as an example. Absent. For example, the holder 20 may be provided on the upper side of the battery module 1 and the discharge space S may be arranged on the upper side of the battery module 1.

  In this case, the locking part 24 and the locking surface 24a are provided on the lower surface 22 side facing the upper surface 23 of the holder 20 where the discharge space S is located. The folded portion 43 is provided so as to restrict the cover member 40 from moving upward in the Z direction due to gas pressure. And the sealing member 60 is provided between the inner surface of the folding | returning part 43, and the latching surface 24a which faces a Z direction downward. With this configuration, when the gas is ejected from the unit cell 10, a compressive force is applied to the seal member 60 in the same direction as the direction in which the lid 41 is pushed by the gas pressure, and the necessary sealing performance is exhibited. Can do. In addition, the cover member 40 maintains the state where the discharge space S is formed in a state where the gas is not discharged from the unit cell 10 (a state where the gas is not pressed by the gas pressure) (the inner surface of the lid portion 41). Can be attached to the holder 20 so as not to contact the upper end surface 23 of the holder 20).

1: battery module, 10: single cell, 11: upper end surface (positive electrode terminal), 12: lower end surface (negative electrode terminal), 13: valve, 20: holder, 21: opening, 22: lower end surface, 23: upper end surface 24: locking part, 24a: locking surface, 30: module case, 40: cover member, 41: lid part, 42: side wall part, 43: folding part, 44: outlet, 51, 52: bus bar, 60 : Seal part, S: Discharge space

Claims (1)

A plurality of power storage elements extending in a predetermined direction and arranged side by side in a plane orthogonal to the predetermined direction;
A plurality of openings into which each of the plurality of power storage elements is inserted, and a holder for holding one end of each power storage element in the predetermined direction;
A cover member for forming a space for discharging gas generated in the electricity storage element that is discharged from a discharge valve provided on one end side of the electricity storage element exposed from the plurality of openings, between the holder and the holder; ,
A sealing member for sealing the discharge space,
The cover member is provided on a second surface side facing the first surface of the holder facing the discharge space in a direction in which the cover member is pressed by the pressure of the gas discharged into the discharge space, A folding portion for restricting movement in the pressed direction;
The seal member is provided between the folded portion and the second surface so as to surround the plurality of power storage elements, and when the gas is discharged into the discharge space, the pressing portion presses the sealing member. The power storage module is compressed in the same direction as the direction in which it is applied.

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